Sternal instability is an abnormal motion of the breastbone after open chest surgery. Detection of sternal instability is complex, because it is an abnormal condition that is obscured and manifests itself differently in each case. Surgeons rely primarily on manual examination techniques, such as palpation. In palpation regional tenderness and motion between sternal halves is estimated manually. However, this evaluation is subjective, essentially qualitative and prone to errors. In addition, imaging methods such as chest X-ray and computerized tomography, CT, are used for defining bone separation and fragmentation, but they may fail to indicate small movements of the sternal halves when they are still tightly held together. In addition, X-ray and CT devices are not available everywhere, radiation of X-ray device is not suitable to be used frequently and CT is a quite expensive solution for defining sternal instability. X-ray may also indicate that the sternum is in two parts, even if it is already in one part.
There is, therefore, a need for a noninvasive solution that defines sternal stability in a reliable, accurate and objective way. This kind of solution gives doctors measurement data about the state of the sternum. The doctors may use this data for prescribing of the most suitable treatment that could range from conservative monitoring and advice on daily routine activities to invasive revision of the operation.